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ปฏิกิริยา A + B → AB เป็นปฏิกิริยาชนิดใด

1. Aการเผาไหม้
2. Bการสังเคราะห์ (การรวมตัว)
3. Cการแทนที่เดี่ยว
4. Dการสลายตัว

Which element has the symbol Fe?

1. AIron
2. BFermium
3. CFrancium
4. DFluorine

Which property is typical of bases?

1. AThey have a pH below 7
2. BThey taste sour
3. CThey turn blue litmus red
4. DThey feel slippery

In 2KClO₃ → 2KCl + 3O₂, how many moles of O₂ form from 4 mol of KClO₃?

1. A6 mol
2. B8 mol
3. C4 mol
4. D3 mol

How can you get solid salt back from salt water?

1. AUse a magnet
2. BFilter the solution
3. CEvaporate the water
4. DFreeze the solution and lift out the salt

Why do group 1 metals such as sodium react so easily?

1. ATheir nuclei contain no neutrons
2. BThey have a full outer shell of electrons
3. CThey have one outer electron that is easily lost
4. DThey easily gain one extra electron

Cells oxidise glucose to CO₂ and water, as burning glucose does. How does cellular respiration differ from burning?

1. AIt does not need oxygen at any stage
2. BIt releases the energy in many small, enzyme-controlled steps
3. CIt produces different products from burning
4. DIt releases much more total energy than burning the same glucose

Making ammonia (N₂ + 3H₂ ⇌ 2NH₃) is exothermic. A low temperature would give a higher yield, yet factories use a moderately high temperature. Why?

1. AAt low temperatures the reaction is too slow to be useful
2. BLow temperatures would make the ammonia explode
3. CHigher temperatures shift the equilibrium toward more ammonia
4. DThe catalyst only works when the reaction is endothermic